Magmatic Activity and Tectonic Significance in the Xiong'ershan Area during the Neoarchean to Early Paleoproterozoic
Liu Heng
Liu Lei
Zhang Dexian
Kang Shisheng
Hu Tianyang
Abstract：The ancient rocks exposed along the southern margin of the North China Craton primarily comprise a suite of rocks known as TTG(Tonalite-Trondhjemite-Granodiorite)and K-rich granites.This suite represents a critical target for the study of granite genesis and the evolution of continental crust.This paper focuses on the Xiong'ershan region and employs zircon microanalysis of Hf-O isotopes and trace elements to trace the evolution of magma.It explores the geochemical characteristics of granites at different stages,the nature of their source regions,and the mechanisms behind their formation.This study identifies two significant magmatic-tectonic events around 2.5 to 2.4 Ga and～2.3 Ga.The research reveals that in the Xiaonangou region,trondhjemite from 2.51 to 2.43 Ga contain rich titanium oxides,with low εHf(t)values ranging from-6.9 to+5.0.The zircon oxygen isotope values average 6.03‰ and 5.18‰,suggesting potential associations with partial crustal melting and the incorporation of sedimentary material.In the Huanggou and Muce regions,～2.3 Ga potassic granites exhibit zircon oxygen isotope values averaging 3.98‰ and 3.10‰,with enriched εHf(t)values ranging from-5.8 to-3.5,respectively.The significant decrease in zircon δ18O values may be linked to high-temperature hydrothermal-magmatic interactions caused by upwelling mantle material.Zircon trace element compositions of different types in granites from different eras exhibit characteristics of continental arc environments.Combined with continuously low εHf(t)and reducing δ18O isotopic composition,the Xiong'ershan region likely formed in an active continental margin arc environment on the eve of the magmatic quiet period.
Keywords：zircon Hf-O isotopeoxygen fugacitythe southern margin of the NCC2.5～2.3 GaActive continental marginstructural geology
Publication Date：2025-02-14
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：20( 667-686 )